Technology: The Heat is On

Warm solvent vapour technology changes the rules…again.

by Jess Sinclair

Steam Assisted Gravity Drainage (SAGD) has done wonders for Canada’s heavy oil industry. The technology, conceived in the 1970s by Irving oil Engineer Dr. Roger Butler, has been perfected over the last generation by Canadian oilsands producers.

But there’s a new technological innovation that is poised to give SAGD a run for its money.

Canadian tech company NSOLV has tasked itself with the challenge of solving some of the most daunting operational and environmental issues within the country’s heavy oil industry. SAGD may be revolutionary, but it also requires significant water and energy to heat viscous oilsands bitumen to the point where it can be efficiently extracted. This was a reality that NSOLV’s clean technology team was keen to address.

Enter the company’s warm solvent vapour technology (WSVT). It aims to reduce the resources needed to bring heavy oil products to an appropriate extraction viscosity. The method sounds like it’s right out of a science fiction novel. Pure heated solvent vapour is injected into a bitumen reservoir, where it condenses and dissolves the bitumen so that it can be extracted by gravity drainage to a producing well. The method uses the same horizontal wells that have been tried, tested and true in northern Alberta and other jurisdictions for generations.

Sounds amazing, right? The benefits of the technology don’t stop there. The solvent (simply propane or butane) separates and leaves behind much of the dirty part of the barrel. Sulphur, heavy metals and carbon residue are removed, meaning that a barrel of WSVToil is actually more immediately marketable than a barrel of typical oilsands crude. Imagine oil coming out of the ground already partially upgraded. This makes the WSVT barrel more valuable and requires much less diluent than traditional bitumen production.

WSVT technology represents another leap forward for Alberta’s oilsands technology, and the applications may apply other heavy oil types as well. The company’s efforts represent an important fusion of clean and hydrocarbon technology, one that we are seeing more and more of thanks to organizations like the Canadian Association of Oilsands Innovation Alliance and the Natural Gas innovation Fund. This is the future of oil and gas and Canadian industry is at the forefront. Yet another reason we are best-in-class when it comes to our ever-growing contribution the global energy mix.  ν

How It Works

Step 1 – Solvent purification.
The WSVT process requires a substantially pure solvent in order to function effectively; therefore, the first step in the process is to distill the solvent, removing non-condensable gases such as methane, turning it into a high-purity solvent.

Step 2 – Solvent heating.
The high-purity solvent is then warmed and turned into solvent vapour.

Step 3 – Solvent vapour injection.
Warm solvent vapour is pumped into the injection well at a rapid pace. When it reaches the extraction chamber, it condenses and dissolves the bitumen, draining downward to the production well as a solution of both solvent and oil. Naturally occurring water and non-condensable gases are also carried along and out of the reservoir. Coke-forming asphaltenes are sequestered.

Step 4 – Separation.
Upon being pumped up to surface, the partially upgraded oil mixed with solvent is separated into three components: oil for sale, solvent and naturally occurring water. The oil is sent to refineries for further processing. The solvent is pumped back into the separator and re-purified before being recycled back into the reservoir. Gaseous impurities removed from the solvent, such as methane, are used to fire up the solvent heater.

Step 5 – Solvent make-up.
Nsolv estimates that a solvent quantity equivalent to 20–30% of the extracted oil must be added to the system as make-up. As the chamber grows, the make-up solvent is continually replenished. At the end of a well’s life, the solvent can be recovered and reused on another well or marketed.